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• Adding prebuild static library to android studio

  24 mars 2017, par David Barishev

  I have build ffmpeg libraries statically for x86 android using a custom configuration.Now i wanted to add them in my android project.

  Im using ffmpeg 3.2.git, android studio 2.3.

  I created a folder named distribution which had my binaries, located the root of my project.
  Here is a file tree :

  |__distribution
  
  | |__avcodec
  
  | | |__include
  
  | | | |__avcodec.h
  
  | | |__lib
  
  | | | |__x86
  
  | | | | |__libavcodec.a
  
  | |__avfilter
  
  | | |__include
  
  | | | |__avfilter.h
  
  | | |__lib
  
  | | | |__x86
  
  | | | | |__libavfilter.a
  
  | |__avformat
  
  | | |__include
  
  | | | |__avformat.h
  
  | | |__lib
  
  | | | |__x86
  
  | | | | |__libavformat.a
  
  | |__avutil
  
  | | |__include
  
  | | | |__avutil.h
  
  | | |__lib
  
  | | | |__x86
  
  | | | | |__libavutil.a
  
  | |__swresample
  
  | | |__include
  
  | | | |__swresample.h
  
  | | |__lib
  
  | | | |__x86
  
  | | | | |__libswresample.a

  I edited my cmake to include the libraries :

  add_library(
  
           native-lib
  
           SHARED
  
           src/main/cpp/native-lib.cpp )
  
  
  
  set(distribution_DIR ${CMAKE_SOURCE_DIR}/../distribution)
  
  
  
  add_library(lib_avcodec STATIC IMPORTED)
  
  set_target_properties(lib_avcodec PROPERTIES IMPORTED_LOCATION
  
      ${distribution_DIR}/avcodec/lib/${ANDROID_ABI}/libavcodec.a)
  
  
  
  add_library(lib_avfilter STATIC IMPORTED)
  
  set_target_properties(lib_avfilter PROPERTIES IMPORTED_LOCATION
  
      ${distribution_DIR}/avfilter/lib/${ANDROID_ABI}/libavfilter.a)
  
  
  
  add_library(lib_avformat STATIC IMPORTED)
  
  set_target_properties(lib_avformat PROPERTIES IMPORTED_LOCATION
  
      ${distribution_DIR}/avformat/lib/${ANDROID_ABI}/libavformat.a)
  
  
  
  add_library(lib_avutil STATIC IMPORTED)
  
  set_target_properties(lib_avutil PROPERTIES IMPORTED_LOCATION
  
      ${distribution_DIR}/avutil/lib/${ANDROID_ABI}/libavutil.a)
  
  
  
  add_library(lib_swresample STATIC IMPORTED)
  
  set_target_properties(lib_swresample PROPERTIES IMPORTED_LOCATION
  
      ${distribution_DIR}/swresample/lib/${ANDROID_ABI}/libswresample.a)
  
  
  
  
  
  
  
  include_directories(
  
                             ${distribution_DIR}/avcodec/include
  
                             ${distribution_DIR}/avfilter/include
  
                             ${distribution_DIR}/avformat/include
  
                             ${distribution_DIR}/avutil/include
  
                             ${distribution_DIR}/swresample/include)
  
  
  
  
  
  target_link_libraries( 
  
                         native-lib
  
  
  
                         lib_avcodec
  
                         lib_avfilter
  
                         lib_avformat
  
                         lib_avutil
  
                         lib_swresample
  
                          )

  I also restricted the build to only x86, in my app build.gradle :

  ndk {
  
              // Specifies the ABI configurations of your native
  
              // libraries Gradle should build and package with your APK.
  
              abiFilters 'x86'
  
      }

  The project gradle sync worked successfully.
  I edited my cpp file to try to use the libraries, and i noticed something weird,i couldn’t reference the headers with the library beforehand, only the header name itself (eg. #include "libavformat/avformat.h" doesn’t work, #include "avformat.h" works).
  I suspect this is because of the headers reference, that they are not tied to a library.
  How can i fix it ?

  Also this makes the project build fail, since in the static libraries headers, there is a reference to other part of the library (eg avformat includes avcodec),but they reference it with the library name beforehand, and as i have said earlier, it doesn’t work.

  Here is the relevant build log part :

  ../../../../../distribution/avformat/include\avformat.h:319:10: fatal error: 'libavcodec/avcodec.h' file not found
  
    #include "libavcodec/avcodec.h"
  
             ^

• Raspberry Pi : Playing multiple video files in mkfifo pipe

  19 janvier 2017, par user3246167

  I have 2 files, test.mp4 and test2.mp4 that I want to play concurrently with no noticeable break in the middle. Currently I’m using

  mkfifo test
  
  cat test.mp4 > test &
  
  cat test2.mp4 > test &
  
  omxplayer test

  However, when I do this, omxplayer just returns data and doesn’t play the file. But if I just put a single file into the pipe, omxplayer shows it normally. I’ve also tried using the copy command in ffmpeg, and that also just returns data, doesn’t play the file.

  I understand that I can just concatenate the 2 files together, but that will not work for my purposes, because I will need to be able to feed files to the pipe while omxplayer is running

• FFmpeg and h264_qsv

  16 juin 2015, par Dmitry Vasilyev

  I use Intel Quick Sync encoder inside FFmpeg for h264 RTSP streaming.

  find_hwaccel method from utilc.c is used for filling hwaccel structure.

  libx264 encoder is working with AV_PIX_FMT_RGB24 or AV_PIX_FMT_NV12 formats. But h264_qsv requires AV_PIX_FMT_QSV.

  Method vpicture_get_size(AV_PIX_FMT_NV12, width, height) returns correct size. But method vpicture_get_size(AV_PIX_FMT_QSV, width, height) returns -22
  In addition, method avcodec_encode_video2 crashes when context is filled with AV_PIX_FMT_QSV format.

  What is the reason of such behavior ?